So over the last few days i noticed that when i would start my truck up in the morning, i could hear the belt making a lot of noise, but it would go away after about 10 min of driving as it would warm up. Now as of the last 2 days i notice it all the time now especially at idle. How can I tell if its the belt that needs to be changed or the belt tension-er? TOTAL newb question I know, but help me out if you have a heart. Heres my rundown.
2001 SR5 4x4 Taco 86,000 miles, Auto tranny. Thanks!

 

So you have it narrowed down to only two possibilities? Are you sure? What's the noise sound like? Could it be a bearing in either the water pump or one of the idlers, maybe?

Are you sure it's timing belt related and not a noise cause by one of the accessory belts or components? More details needed please.

 

Its not that Squeeky cricket sound that water pump stuff usually seems to make. It's a very dry scratchy sound "schhh schhh schhh". When I pop the hood it definitely sounds like its coming from the main belt. Also I have been doing some reading on here and 90,000 miles seems to be the common lifespan everyone on here talks about regarding the main belt. Im at 86,000 so i just kinda figured that might be it. What other component would cause this sound, especially make it sound like its coming from the belt? Thanks!

 

You can try removing all the accessory belts and see if it is the timing belt. If it isn't then put the belts back on one at a time and see which one makes the noise.

 

OK... well, I'd be very surprised if there was something wrong with your tensionner already at that mileage and age, but you never know. If there was though, you'd be jumping teeth on your belt timing. Maybe something is bent, and causing the edge of the belt to rub somewhere. Take your timing cover off and see if you see any wear marks on the edges of the timing belt.

 

Gotcha, Ill give that a try tomorrow, Thanks! What would be bent though? Will wear marks be really noticeable?

 

If it is actually the timing belt edge that's rubbing up against something (like the lip on one of the pulleys), it could be caused by excessive runout either in a camshaft or in the crankshaft, or by a worn idler, I guess. Anything that would cause one of your pulleys or idlers to be rotating on a slightly different axis than the others. That would cause your belt to want to "walk off" the pulleys and could cause it to continuously rub up against the retaining lip of the pulleys.

I would think this would be a relatively rare occurance, but it's possible in theory.

I would start with the easy stuff first (removing the three accessory belts and seeing if the noise goes away).